1. Field of the Invention:
This invention relates to an apparatus for inserting a flattened metal wire, the flat surfaces of which are set vertical, into a cylindrical container while forming the flattened wire into continuous spiral loops, in such a manner that these loops are stacked in this cylindrical container without being twisted with the loop-forming positions therein staggered sequentially. The invention also relates to an apparatus for feeding the flattened metal wire without twisting the loops from the interior of the cylindrical container to the exterior thereof continuously, and more particularly to an apparatus for inserting into, and an apparatus for feeding therefrom a flattened copper wire used for electric welding.
2. Description of the Prior Art:
There is a known apparatus for taking up and rewinding a steel wire of high strength, in which a steel wire is taken up as a reel is rotated, the steel wire thus taken up being rewound as the reel is rotated in the reverse direction.
Japanese Patent Publication No. 39191/1979 discloses a method of taking up in a coiled state a steel wire of high strength in a cylindrical container or around a reel, and then withdrawing the coiled wire while rewinding the same. In this method, a steel wire is taken up as it is twisted 360.degree. per loop without rotating the cylindrical container or reel, and then rewound as it is twisted 360.degree. per loop in the reverse direction.
However, the wire taken up and rewound in this method is a wire having a circular cross section, and it is very difficult to employ this method for taking up and rewinding a flattened metal wire. When a flattened metal wire is taken up as a reel is rotated, the diameter of the wound part of the metal wire increases as the winding thereof progresses, and, therefore, the radii of curvature of different parts of the wound metal wire are unequal. Hence, it is very difficult to take up and rewind such a metal wire without twisting the same.
Moreover, as the winding of the flattened metal wire progresses, the length of each loop differs. Therefore, in order to take up and rewind the flattened metal wire at a constant rate, it is necessary to regulate the rotational speed of the reel in accordance with the variations of the diameter of the wound metal wire. In order to use this flattened metal wire as a welding electrode wire, it is necessary to control the winding rate and feed rate while maintaining a constant posture of the wire, in accordance with the welding rate.
An experiment was made to take up a flattened metal wire while twisting the same at 360.degree. per loop, without rotating a cylindrical container or a reel, as in the method disclosed in Japanese, Patent Publication No. 39191/1979. The result was that the metal wire could not constantly be taken up. Namely, as the flattened metal wire has a nearly-rectangular cross section and different longitudinal and lateral section moduli, it did not form loops of a constant radius, unlike a metal wire of a circular cross section, during the twisting of the metal wire being taken up. In concrete terms, the flattened metal wire thus taken up became elliptic and failed to have a horizontal predetermined shape.
An electrode wire used in a conventional electric resistance welding apparatus (FIG. 1) for cans consists of a copper wire 20 of a circular cross section. Before this copper wire has been fed onto a welding roll 11, it is compressed to a flat shape to be used as a flattened copper wire 10. After the flattened copper wire has been passed through a welding zone and sent out from a welding machine 14, it is cut to a length of around 35-40 mm with a cutter 21, or taken up suitably and disposed as scrap.